Electric switch



y 1, 1940- F. D. BRYANT EFiAL ,88

ELECTRIC SWITCH Filed Feb. 15, 1939 h"? erfitors: Frank D. Brgant, William P. Young,

by )VwydM Their Attorneg.

Patented May 21, 1940 ELECTRIC SWITCH Frank D. Bryant, Stratford, and William R. Young, Fairfleld, Conn, assignors to General Electric Company, a corporation oi. New York Application February 15, 1939, Serial No. 256,516

13 Claims.

The present invention relates to electric switches, and more particularly to a rotary switch adapted to control a plurality, of circuits.

Switches of this type have a wide application.

They are well adapted for use in connection with speed control circuits for electric motors.

It is an object of this invention to provide a simple and rugged switch construction which is easily operated and which insures a circuit connection of low electrical resistance.

It is another object of this invention to provide an electric switch having relatively few parts which are easily assembled and which may be manufactured at low cost.

Further objects and advantages of the present invention will become apparent as the following description proceeds, reference being had to the accompanying drawing in which Fig. 1 is a plan view partly broken away, of a switch embodying our invention; Fig. 2 is a sectional view taken along the line '2 2 of Fig. i; Fig. 3 is a sectional view along the line 3-3 of Fig. l, and Fig. 4 is an exploded view of the switch shown in Fig. 1 showing the details of construction of the vaiious parts of the switch.

As illustrated in the drawing a support or housing for the switch mechanism is provided by the body ill and the thumb cap or cup-shaped operating member ll, both of which are formed of an insulating material such as a molded phenolic condensation product. I 1e body is of generally cylindrical form and includes a flange l2 and an upstanding boss I3. A recess i l opening on the lower face of the flange is defined by a wall It of generally annular shape which serves as a support for a plurality of conducting members ii. The conducting members It which form the stationary contact and terminal structure of the switch are preferably sheet metal stampings of substantially U-shape.. One arm of each U-shaped member forms a contact I! having a V-shaped cross-section to provide two opposing contact "surfaces, while the other arm of the U forms a terminal or supporting arm l8. The circuit wires is are secured to the terminals in any suitable manner as by soldering. The annular wall I5 is provided on its outer and inner surfaces with a plurality of circumferentially spaced axially extending grooves 20 and 2| which are adapted to receive the contacts and terminals respectively. The grooves 20 are of the same size and contour as the contacts Il so that the outer surfaces of the contacts are flush with the outer surface of the switch body. The grooves 20 and 2| are positioned in radial alinement and are connected on the face of the flange It by radially extending recesses 22 which are adapted to receive the bases of the U-shaped conducting members. The grooves 20 on the outer surface of the wall 15 extend through the flange l2 and permit the U-shaped conducting members to be assembled on the base by simply slipping them over the annular wall with each arm of the U accommodated in one of the radially alined grooves.

Axially extending barriers or ribs 23 formed on the inner surface of the wall l5 between the grooves 2i serve to separate the conductors attached to the different terminals and diminish the possibility of a short circuit being established.

The conducting members 16 are held assembled on the annular wall l5 by an insulating washer 24 and an overlying metal plate at secured against the face of the flange I2 by screws 25 which engage the walls of suitable threaded openings 26 formed in the flange. Centrally located apertures 21 are formed in the washer 24 and plate Z ta for the reception of the circuit wires it. A threaded nipple 28 having an end received in the aperture 2! of the plate 24a and secured thereto in any suitable manner provides a convenient means for mounting the switch. The nipple also provides a conduit for the circuit wires as they enter the switch body. Depending legs 23 formed on the plate 24a. are adapted to engage notches 30 formed at diametrically opposite points on the outer edge of the washer 24 and the flange l2 to position the parts relative to each other.

For operating the switch the thumb cap H is rotatably mounted on the switch body It by a boss or hub 3i which is journaled in a bore 32 opening on the face of the boss portion l3 of the insulating body. The bore 32 opens at its other end on the floor of the recess l4 which is of larger diameter than'the bore so that a shoulder 33 facing the flange I2 is provided. An insulating washer 34, secured to the hub 3| of the thumb cap by a suitable screw 35, engages the shoulder 32 to hold the thumb cap and switch body in operative relationship. An annular wall 36 depending from the face of the thumb cap surrounds the boss l3 of the switch body in spaced relation thereto. At one side the wall is provided with a thickened portion 31 which is provided with a member received in one pair of the radially alined 40 may be considered as comprising a post 4| formed integrally with the thumb cap and extending in spaced relation to the wall 36.

The movable bridging member is of substantially U-shape having a pair of opposed resilient arms 42 each of which is provided near its outer end with a spherical contact surface 43 which is struck up from the body of the bridging member. Spherical or ball contacts 44 are arranged in the bearing surfaces and are adapted to be pressed against the outer surface of the boss 13 of the insulating body by the resilient arms 42. When the thumb cap is rotated it carries with it the bridging member 40 and its associated contacts t l which are moved from one set of contacts ll to another to electrically connect the contacts located at diametrically opposite points on the switch body.- Airially extending ribs 45 formed between the contacts ii on the outer surface of the boss i3 cooperate with the spherical contacts M and the resilient arms 42 of thebridging member it to move the spherical contacts from one circuit-controlling position to another with a snap action when the thumb cap l l is rotated. The opposed sides of the ribs 45 are substantially plane surfaces and lie in the same plane as the adjacent legs of the V-shaped contact members It. In other words, the outer surface of the switch body is a succession of hill and valley portions with the trough of each valley formed by one of the V-shaped contact members I! and the crest of each hill formed by one of the axially extending ribs 45. With this construction the spherical contacts follow the contour of the outside surface of the switch body under the action of the resilient arms 42. It is apparent that the spherical contacts always tend to return to the troughs formed by the contacts H and, in this way, position the fixed and movable parts of the switch relative to each other. Since the spherical contacts are free to rotate relative to the bearing surfaces formed in the resilient arm, the force required to rotate the thumb cap is reduced to a minimum.

In order to provide an off position, no contacts are provided on the opposed surfaces 46 of the boss 53. These surfaces have the same V- shape as those formed by the stationary contacts :1 and the ribs 45. It is apparent that the switch may be rotated in either direction from one circuit-controlling position to another. In order to indicate the position of the spherical contacts relative to the switch body the thumb cap II is provided with an indicating arrow 41.

While we have shown and described a switch construction in which six stationary. contact elements are arranged to provide three on-circuit positions of the switch, it is to be understood that any number of contacts may'be arranged on the switch body at diametrically opposite points, and that any desired number of "ofi positions may be provided by simply omitting pairs of contacts and grooves and leaving in place thereof opposed faces of the boss l3 of insulating material.

The switch described above is very easily assembled. After the circuit wires 9 have been secured to the terminals of the U-shaped conducting members IS, the latter are assembled on the switch body by simply slipping them over the annular wall I5 with the legs of each U-shaped grooves 20 and 2| formed on the outer and inner surfaces of the annular wall. The insulating washer and metal plate 24 and 24a are then secured against the face of the flange by screws .the boss 3| in the bore 32. The assembly is completed by inserting the washer 34 and screw in the recess l4 and threading the screw into the boss 3i of the thumb cap. When theswitch is assembled the flange 52 of the switch body serves to hold the conducting member assembled in the thumb cap.

From the foregoing it is clear that a very compact and rugged switch construction is provided by the present invention in which movable contacts may be moved with a snap action in either direction from one circuit-controlling position to another by simply rotating the thumb cap which carries with it the movable contact structure. The resilient arms of the movable contact structure cooperate with the ball contacts and the stationary contact members to insure good electrical connections and at the same time the rolling action of the ball contacts provides a. switch which is very easily operated.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a switch, a body of insulated material having a substantially annular shaped Wall, said wall having a plurality of spaced axially extending grooves on the inner and outer surfaces thereof, a plurality of stationary conducting members of U-shape each having a contact portion positioned in a groove on the outer surface of said wall and a terminal portion positioned in a groove on the inner surface of said Wall, an operator of insulating material rotatably mounted on said body, a pair of spherical contact members, a bridging member of conducting material carried by said operator and having oppositely disposed arms adapted to receive said spherical contact members and hold them against the outer surface of said annular wall to connect electrically certain of the conducting members located in said grooves.

2. In a switch, a body of insulating material including a raised central portion, a plurality of conducting members mounted in spaced relation on the outer surface of said central portion, a cap of insulating material rotatably mounted on said body, a substantially U-shaped bridging member of conducting material mounted in said cap and having a driving connection therewith, said bridging member having oppositely disposed arms straddling said central portion, and contacts associated with the arms of said bridging member for engaging certain of said conducting members.

3. In a switch, a body of insulating material having a substantially annular shaped wall, a plurality of stationary conducting members of U-shape arranged in spaced relation on said wall, each of said conducting members having a contact portion positioned on the outer face of said wall and'a supporting portion positioned on the inner face of said wall, a cap of insulating material rotatably mounted on said base, a substantially U-shaped bridging member of conducting material mounted in said cap and having oppositely disposed arms spanning said annular wall, and contacts associated with the arms of said bridging member for engaging certain of the contact portions of said conducting members.

Ill

4. In a switch, a body of insulating material having a substantially annular shaped wall, said wall having a plurality of spaced axially extend-- ing grooves on the inner and outer faces thereof, a plurality of conducting members of U-shape each having a contact portion positioned in a groove on the outer face of said annular wall and a terminal portion positioned in a groove on the inner face of said wall, a cap, of insulating material-rotatably mounted on said body, said cap having a depending wall surrounding said annular shaped wall, said depending wall having an axially extending slot formed therein, a bridging member of conducting material having an offset portion positioned in said slot for moving said bridging member with said cap, said bridging member including oppositely disposed arms having bearing surfaces formed therein, and spherical contacts positioned in said bearing surfaces adapted to engage the contact portions of certain of said conducting members.

5. In a switch, a body of insulating material having an upstanding boss, an axially extending recess in said boss, a plurality of pairs of axially extending grooves spaced around the outer surface of said boss in diametrically opposed relation, conducting members positioned in said grooves, a cap having a centrally located hub positioned in said recess to mount said cap on said base and permit rotation relative thereto, said cap having a depending wall surrounding said boss, an axially extending slot in said wall, a bridging member of conducting material having an offset portion positioned in said slot for moving said bridging member with said cap, said bridging member including oppositely disposed arms having contact surfaces associated therewith arranged to electrically connect the conducting members located in any one of said pairs of diametrically opposed grooves.

6. In an electric switch, a body of insulating material having a flanged portion and an upstanding boss, a plurality of conducting members secured in spaced relation around the outer surface of said boss, a thumb cap rotatably mounted on said body, a substantially U-shaped bridging member of conducting material slidably mounted in said cap and having a driving connection therewith, the opposed arms of said U-shaped member having contacts carried thereby adapted to engage certain of said conducting members, said flanged portion being constructed and arranged to engage the lower edge of said bridging member to hold it assembled in said thumb cap. 7. In a switch, a body of insulating material having a flanged portion and an upstanding boss, a recess opening on the face of said flange and a recess of smaller diameterlopening on the face of said boss, a shoulder formed on said body at the junction of said recesses, a plurality of axially extending grooves on the outer face of said boss, conducting members positioned in said grooves, a cup-shaped cap member having a centrally disposed hub adapted to extend into said smaller recess and postion said cap on said body and permit rotation relative thereto, an axially extending post on said cap, a bridging member of conducting material having an offset portion adapted to engage said post to form a driving connection between said cap and said bridging member, said bridging member having oppositely disposed arms spanning said boss, said arms having spherical bearing surfaces formed in the ends thereof, spherical contact members positioned in said bearing surfaces and pressed against the outer surfaces of said boss portion by the resilient arms of said bridging member, and means secured to said hub for engaging said shoulder to hold said cap on said base.

8. In an electric switch for controlling a plurality of circuits, a body of insulating material having a flanged portion and an upstanding boss, said body having an axially extending bore formed therein, a plurality of axially extending grooves on the inner and outer surfaces of said body, a plurality of U-shaped conducting members having their opposite arms received in said grooves, 21. cup-shaped operating member having a centrally disposed hub extending into said bore to position said operating member on said body and permitting rotation relative thereto, an axially extending post formed on said cap, a bridging member of conducting material having an offset portion engaging said post to form a driving connection between said operating member and said bridging member, said bridgmg member having oppositely disposed resilient arms spanning said boss, and contact surfaces associated with said arms and pressed against the outer surface of said boss by the resilient arms of said bridging member whereby rotation of said cap moves said bridging member and its associated contacts from one circuit-controlling position to another.

9. In a switch for controlling a plurality of circuits, a body of insulating material having a flanged portion and an upstanding boss, conducting members secured in spaced relation around the outer surface of said boss, an axially extending recess opening on the face of said boss, a cupshaped cap member having a centrally disposed hub extending into said recess to position said cap on said body and permit rotation relative thereto, a U-shaped slot in the wall of said cap, a bridging member of conducting material having an offset portion positioned in said slot to form a driving connection between said cap and said bridging member, the flanged portion of said base being constructed and arranged to engage the lower edge of said bridging member to hold it in said cap, said bridging member having resilient oppositely disposed arms spanning said boss, said arms having spherical bearing surcircuits, a body of insulating material, a plurality of contacts arranged in spaced relation around the outer surface of said body, axially extending ribs formed on said body between adjacent contacts, an operating member of insulating material rotatably mounted on said body, a bridging member of conducting material secured to said operating member and adapted to rotate therewith, said brldging member having resillent oppositely disposed arms spanning said body, said arms having spherical bearing surfaces formed near the ends thereof, spherical contact members positioned in said bearing surfaces and pressed against the outer surface of said body by the resilient arms of said bridging member, said axially extending ribs cooperating with said resilient arms and said spherical contact members to move said contact members from one circuit-controlling position to another with a snap action when said operating member is rotated.

11. In a switch, a body of insulating material having a substantially annular-shaped wall, said wall having a plurality of spaced axially extending grooves on the inner and outer surfaces thereof, a plurality of stationary conducting members of U-shape each having a contact portion positioned in a groove on the outer surface of said wall and a terminal portion positioned in a groove on the inner surface of saidwall, an operator of insulating material rotatably mounted on said body, and means of conducting material carried by said operator and movable therewith to connect electrically certain of the conducting members located in said grooves, said means including a pair of spherical contact members and a pair of oppositely disposed arms adapted to receive said contact members and hold them against the outer surface of said annular wall and the conducting members positioned thereon.

12. In a switch, a body of insulating material having a substantially annular-shaped wall, a plurality of stationary conducting members of U-shape arranged in spaced relation on said wall, each of said conducting members having a contact portion positioned on the outer face of said wall and a supporting portion positioned on the inner face of said wall, and meanssecured to said body and engaging said conducting members to prevent their removal from said wall, an operating member of insulating material rotatably mounted on said base, and means of conducting material mounted in said operator, said means including a pair of oppositely disposed arms spanning said annular wall and contacts associated therewith for engaging the contact portion of certain of said conducting members.

13. In a switch for controlling a plurality of circuits, a body of insulating material, a plurality of contacts arranged in spaced relation around the outer surface of saidbody, axially extending ribs formed on said body between adjacent contacts, an operating member of insulating material rotatably mounted on said body, means formed of conducting material secured to said operating member for rotation therewith, said means including oppositely disposed resilient arms spanning'said body, said arms including spherical bearing surfaces formed near the ends thereof, spherical contact members positioned in said bearing surfaces and pressed against the outer surface of said body by said resilient arms, said axially extending ribs cooperating with said resilient arms and said spherical contact members to move said contact members from one clrcuit-controlling position to another with a snap action when said operating member is rotated. FRANK D. BRYANT. WILLIAM R. YOUNG. 

